From secnotif@MICROSOFT.COM Thu Sep 6 18:49:19 2001
From: Microsoft Product Security
To: MICROSOFT_SECURITY@ANNOUNCE.MICROSOFT.COM
Date: Thu, 6 Sep 2001 16:26:07 -0700
Subject: Microsoft Security Bulletin MS01-047
The following is a Security Bulletin from the Microsoft Product Security
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Title: OWA Function Allows Unauthenticated User to Enumerate
Global Address List
Date: 06 September 2001
Software: Exchange 5.5
Impact: Information Disclosure
Bulletin: MS01-047
Microsoft encourages customers to review the Security Bulletin at:
http://www.microsoft.com/technet/security/bulletin/MS01-047.asp.
- ----------------------------------------------------------------------
Issue:
======
Among the functions Outlook Web Access (OWA) in Exchange 5.5 offers
is the ability to search the global address list (GAL). By design,
this is an authenticated function, implemented as a two-tier
architecture - a front tier that provides a user interface and a
back-end tier that actually performs the search. However, only the
front tier actually checks authentication. An attacker who sent a
properly formatted request to the back-end function that actually
performs the search could enumerate the GAL without authenticating.
Mitigating Factors:
====================
- The vulnerability would only allow the attacker to learn
users' email aliases. It would not provide any other
capabilities. Specifically, it would not give the attacker
any way to create or send mail as a user; to read, change
or delete mail; or to perform any other functions on the
server.
- The vulnerability is only exploitable via OWA. Exchange
servers that are not configured to offer OWA are not affected
by the vulnerability.
- The vulnerability does not affect Exchange 2000, even when
offering OWA.
Patch Availability:
===================
- A patch is available to fix this vulnerability. Please read the
Security Bulletin at
http://www.microsoft.com/technet/security/bulletin/ms01-047.asp
for information on obtaining this patch.
Acknowledgment:
===============
- Noam Rathaus from SecuriTeam.com (http://www.SecuriTeam.com)
- ---------------------------------------------------------------------
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